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My solution: https://github.com/vladstudio/Vladstudio-smart-resize-Bash-s... The biggest problem of scaling down an image is to find right settings for resampling and sharpening. After many expreiments, I found it impossible to achieve good results by simply running convert with a line of arguments. So I came up with this script, which basically does the following: * configures -interpolate bicubic -filter Lagrange;…
Just for the record, the "unsharp mask" filter doesn't really sharpen but it increases edge contrast, which makes it seem sharper. It is something that you should only apply to the final version of an image, after all resizing has been done, however.
Sharpening improves "acutance"; your perception of boundaries. https://en.wikipedia.org/wiki/Acutance Unsharp masking is mostly aesthetic. For an image like the example, a mountainside, it gives you a feeling of crisp details, but there isn't any more data there. It looks great on a landscape, but it can be disastrous on a portrait of a person (pores and stubble will be highlighted, usually in an unpleasant way). (ED…
Unsharp mask doesn't work that way: you get the same results applying it before or after scaling, as long as you adjust the radius accordingly.
The reason I suggested applying it after scaling is because aesthetically pleasing settings don't change much as the image size changes.
I think the script to apply it to a folder could be clear with: for image in *.jpg ; do gm convert $image -resize "900x" -unsharp 2x0.5+0.5+0 -quality 98 `basename $image .jpg`_s.jpg ; done
Much better appearance for the same file size.
My solution: https://github.com/vladstudio/Vladstudio-smart-resize-Bash-s... The biggest problem of scaling down an image is to find right settings for resampling and sharpening. After many expreiments, I found it impossible to achieve good results by simply running convert with a line of arguments. So I came up with this script, which basically does the following: * configures -interpolate bicubic -filter Lagrange;…
Do you have any suggestions when there are thousands of images and all this needs to be automated?